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Stepping up lager starters... talk to me like I'm 4 years old...


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#21 positiveContact

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Posted 02 March 2015 - 03:28 PM

ken, you could up the gravity of that starter slightly (what rich posted) and that would get you a few more cells.



#22 SchwanzBrewer

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Posted 02 March 2015 - 03:29 PM

No problem! Brew On!



#23 neddles

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Posted 02 March 2015 - 05:45 PM

I use a 1 gal. glass jug.  More volume than a flask for a lot less money.  For a lager, I'll use 3 qt. of wort, let it ferment out on the stirplate, crash, decant and feed it another 2 qt.  Let that ferment out, crash, decant and pitch.  Child like enough for ya?  ;)

Maybe I learned it wrong. I thought that you weren't supposed to step *down* a starter like you do going from 3L to 2Qt. My understanding is that there wouldn't be much if any growth in that second starter. Can you fill me in on the logic of why you do it this way?



#24 Brauer

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Posted 02 March 2015 - 06:05 PM

How many cells should I pitch?

OG (in points) * Volume (in Gallons) * (beer style adjustment) = Cells in Billions

Beer Style Adjustment = 0.75 for Ales, 1.0 for Alt, Koelsch or Cream Ale, 1.5 for Lagers 

 

How big a 1.036 starter should I make from a vial (on a stir plate)?

(Cells needed - 100 Billion) / 150 Billion = Starter Volume Needed in Liters 

You can correct for yeast age by reducing the 100 Billion value accordingly.

 

Example:

5.5 gallons of a 1.050 Lager requires 50 * 5.5 * 1.5 = 412.5 Billion cells needed.

(412.5 - 100) / 150 = 2.08 L starter.

 

You can use the same math for a stepped starter, but remember that you won't get as much yeast growth if you go over 130 Billion cells per Liter. Keeping just above the minimum recommended pitch density, a vial of yeast into a 0.75 L starter, dropped out then stepped up to a 1.6 L starter, will yield about 450 Billion cells. 100 + (0.75 * 150) + (1.6 * 150) = 452.5 Billion



#25 Brauer

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Posted 02 March 2015 - 06:25 PM

Maybe I learned it wrong. I thought that you weren't supposed to step *down* a starter like you do going from 3L to 2Qt. My understanding is that there wouldn't be much if any growth in that second starter. Can you fill me in on the logic of why you do it this way?

You will get progressively less growth once you go above 100 Billion cells per 0.75 L. About 1/3 the growth per volume by the time you get to 100 Billion per 0.5 L. That step would probably be around 100 Billion per 0.36 L, which might add another 35-50 Billion cells per Liter to the ~550 Billion from the first step. At that point, the yeast are mostly just eating the wort.



#26 djinkc

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Posted 02 March 2015 - 07:35 PM

How many cells should I pitch?

OG (in points) * Volume (in Gallons) * (beer style adjustment) = Cells in Billions

Beer Style Adjustment = 0.75 for Ales, 1.0 for Alt, Koelsch or Cream Ale, 1.5 for Lagers 

 

How big a 1.036 starter should I make from a vial (on a stir plate)?

(Cells needed - 100 Billion) / 150 Billion = Starter Volume Needed in Liters 

You can correct for yeast age by reducing the 100 Billion value accordingly.

 

Example:

5.5 gallons of a 1.050 Lager requires 50 * 5.5 * 1.5 = 412.5 Billion cells needed.

(412.5 - 100) / 150 = 2.08 L starter.

 

You can use the same math for a stepped starter, but remember that you won't get as much yeast growth if you go over 130 Billion cells per Liter. Keeping just above the minimum recommended pitch density, a vial of yeast into a 0.75 L starter, dropped out then stepped up to a 1.6 L starter, will yield about 450 Billion cells. 100 + (0.75 * 150) + (1.6 * 150) = 452.5 Billion

 

 

You will get progressively less growth once you go above 100 Billion cells per 0.75 L. About 1/3 the growth per volume by the time you get to 100 Billion per 0.5 L. That step would probably be around 100 Billion per 0.36 L, which might add another 35-50 Billion cells per Liter to the ~550 Billion from the first step. At that point, the yeast are mostly just eating the wort.

 

nice review - thanks.



#27 neddles

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Posted 02 March 2015 - 07:41 PM

You will get progressively less growth once you go above 100 Billion cells per 0.75 L. About 1/3 the growth per volume by the time you get to 100 Billion per 0.5 L. That step would probably be around 100 Billion per 0.36 L, which might add another 35-50 Billion cells per Liter to the ~550 Billion from the first step. At that point, the yeast are mostly just eating the wort.

Wish I could remember where I read it but I thought the other downside (other than reduced growth) was increased competition for nutrients and potentially decreased yeast health.



#28 neddles

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Posted 02 March 2015 - 08:18 PM

I use a 1 gal. glass jug.  More volume than a flask for a lot less money.  For a lager, I'll use 3 qt. of wort, let it ferment out on the stirplate, crash, decant and feed it another 2 qt.  Let that ferment out, crash, decant and pitch.  Child like enough for ya?  ;)

Also where do you find a glass jug without a convex bottom? All mine are convex and the stir bar won't stay on it.



#29 Big Nake

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Posted 02 March 2015 - 09:12 PM

Also where do you find a glass jug without a convex bottom? All mine are convex and the stir bar won't stay on it.

Oh, good point. Was the jug I linked to on NB convex-bottomed? Brauer... thanks for your help, as usual. I'll have to put my half-glasses on (a la Homer Simpson) and get a pen and paper out and make sure I know what all that fancy talk was about. :P Cheers to everyone.

#30 Brauer

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Posted 03 March 2015 - 05:04 AM

 

Wish I could remember where I read it but I thought the other downside (other than reduced growth) was increased competition for nutrients and potentially decreased yeast health.

Yes, that's a risk, but I don't know of any particular research that supports that expectation (or refutes it). You are under-supplying nutrients, which is why the growth is stunted. I'd worry about the quality of the new cells, but since there is little growth, you aren't creating a lot of new cells. On the other hand, you are primarily feeding the cells you already grew, so maybe they get a bit of a boost.

 

I always choose the conditions that promote maximal growth, though, figuring that is an indication that the cells are well-fed and healthy.

Oh, good point. Was the jug I linked to on NB convex-bottomed? Brauer... thanks for your help, as usual. I'll have to put my half-glasses on (a la Homer Simpson) and get a pen and paper out and make sure I know what all that fancy talk was about. :P Cheers to everyone.

I use a gallon jug from a gallon of cheap wine. It is a little convex-bottomed, but it works okay on my stir-plate. It might not work on a stir-plate with a weak magnet.

 

The 2 formulas I posted for yeast pitch and starter volume are pretty simple. To me, they're simpler than using an online calculator and easy to remember. Since I used different criteria to determine the curve fit for the growth, you won't get exactly the same result as one of the online calculators. It should be pretty close to one that uses Kai's formulas, though, since I derived my curve fit from his data. You may notice that the calculation for cells needed is very slightly higher than other formulas (~7%), that's just a rounding error that comes from simplifying the formula for someone working in OG and Gallons. If it bugs you, you can use a lower style correction factor (0.7, 0.93, and 1.4), but I just stick with the easier ones to remember and remind myself that the yeast growth calculation is only an estimate. My growth calculation is a little more generous than Kai's, though, so the starter volumes tends to be similar, if that is a comfort.

 

Making a stepped starter cannot be made as simple, unfortunately, and requires a little fiddling to get the numbers you want without over-pitching the second step. I don't need to make stepped-starters for the beers I make, so I usually manage to avoid that math.



#31 positiveContact

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Posted 03 March 2015 - 06:03 AM

just as a reminder - pretty much all of the knowledge that brauer is dropping is built into yeastcalc.  It calculates the right pitching rate for your batch.  It estimates how many cells you are starting with based on yeast manufacture date.  It tells you the amount of water and DME for your starter.  And one of the things people often overlook is it tells you the inoculation rate and if you hover the mouse of that part of the GUI it even tells you what you should be shooting for there.

 

It's an awesome tool - no way around it.


Edited by Evil_Morty, 03 March 2015 - 06:04 AM.


#32 Big Nake

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Posted 03 March 2015 - 08:26 AM

Okay, a couple questions on YeastCalc: If I set things for lager, 1.050, etc. and there is a 2L starter made with 7.1 ounces of DME, it shows the various forms of aeration with Chris White, Jamil, Kai, etc. and it shows that if you start with 100 billion cells you end up with various amounts based in the aeration method... 204 billion, 255, 306, 377, etc. What is the difference between the Jamil stirplate (306 billion) and the Kai stirplate (377)? Also, does anyone have a feel for how long it would take for this starter to complete (2L, 7 ounces DME, one Wyeast Activator). I will have it on a stirplate.

#33 brewman

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Posted 03 March 2015 - 08:42 AM

I find the starter tab of beersmith to be very easy to use.

 

Dan



#34 positiveContact

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Posted 03 March 2015 - 08:50 AM

Okay, a couple questions on YeastCalc: If I set things for lager, 1.050, etc. and there is a 2L starter made with 7.1 ounces of DME, it shows the various forms of aeration with Chris White, Jamil, Kai, etc. and it shows that if you start with 100 billion cells you end up with various amounts based in the aeration method... 204 billion, 255, 306, 377, etc. What is the difference between the Jamil stirplate (306 billion) and the Kai stirplate (377)? Also, does anyone have a feel for how long it would take for this starter to complete (2L, 7 ounces DME, one Wyeast Activator). I will have it on a stirplate.

 

those last two options are just different estimates for cell growth.  I like using kai since it grows more cells :lol:

 

I haven't noticed a significant trend on time to complete if you are pitching at the recommended rates into the starter.  yeast health, type, phase of the moon, etc. seem to have the biggest effect at my house.  usually it's less than 36 hours easy though.  typically probably about 24 hours.



#35 brewman

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Posted 03 March 2015 - 08:56 AM

Most of my starters are 2L and I use 2 cups of DME,  90% of the time its done within 36 hours depending on the temp in the house.

 

Dan



#36 Big Nake

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Posted 03 March 2015 - 09:06 AM

Hmm, well for all the scientific whiz-bangery with Jamil, Kai, etc., that seems like a pretty wide range of yeast growth predictions. According to Jamil I would be 63 billion cells short and according to Kai I would have 8 billion more than I need. It's nothing I would lose sleep over but it's the type of thing that would make my 4-year-old brain wonder. :D

#37 positiveContact

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Posted 03 March 2015 - 09:11 AM

Hmm, well for all the scientific whiz-bangery with Jamil, Kai, etc., that seems like a pretty wide range of yeast growth predictions. According to Jamil I would be 63 billion cells short and according to Kai I would have 8 billion more than I need. It's nothing I would lose sleep over but it's the type of thing that would make my 4-year-old brain wonder. :D

 

I think Kai's is more accurate - or maybe that's just wishful thinking :lol:

 

either way I've had good results using his estimates when making starters.

a little reading for when you have a minute:  https://braukaiser.c...g-yeast-growth/



#38 HVB

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Posted 03 March 2015 - 09:16 AM

I use Kai's as well. A 3 starter seems to take about what 2 days for me.

#39 positiveContact

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Posted 03 March 2015 - 09:22 AM

I use Kai's as well. A 3 starter seems to take about what 2 days for me.

 

so do you see a time to finish difference with different sized starters (assuming similar pitching rates)?



#40 HVB

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Posted 03 March 2015 - 09:31 AM

First, damn the auto correct made that read awful. I just went with a 3l starter because that is what I have made most recently. I think a 1l starter did finish in about 24 hours in the past depending on ambient temperature.


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